ORM: Improvement about foreigh keys

src/main/java/fr/pandacube/java/util/orm/SQLElement.java

@@ -171,14 +171,24 @@ public abstract class SQLElement<E extends SQLElement<E>> {
 				+ " does not exist or is not set");
 	}
 
-	public <T, F extends SQLElement<F>> F getForeignKeyTarget(SQLFKField<E, T, F> field) throws ORMException {
+	/**
+	 * @param <T> the type of the specified field
+	 * @param <P> the table class of the primary key targeted by the specified foreign key field
+	 * @return the element in the table P that his primary key correspond to the foreign key value of this element.
+	 */
+	public <T, P extends SQLElement<P>> P getReferencedEntry(SQLFKField<E, T, P> field) throws ORMException {
 		T fkValue = get(field);
 		if (fkValue == null) return null;
 		return ORM.getFirst(field.getForeignElementClass(),
 				new SQLWhereComp(field.getPrimaryField(), SQLComparator.EQ, fkValue), null);
 	}
 
-	public <T, S extends SQLElement<S>> SQLElementList<S> getForeignKeySources(SQLFKField<S, T, E> field, SQLOrderBy orderBy, Integer limit, Integer offset) throws ORMException {
+	/**
+	 * @param <T> the type of the specified field
+	 * @param <F> the table class of the foreign key that reference a primary key of this element.
+	 * @return all elements in the table F for which the specified foreign key value correspond to the primary key of this element.
+	 */
+	public <T, F extends SQLElement<F>> SQLElementList<F> getReferencingForeignEntries(SQLFKField<F, T, E> field, SQLOrderBy orderBy, Integer limit, Integer offset) throws ORMException {
 		T value = get(field.getPrimaryField());
 		if (value == null) return new SQLElementList<>();
 		return ORM.getAll(field.getSQLElementType(),

src/main/java/fr/pandacube/java/util/orm/SQLElementList.java

@@ -161,7 +161,7 @@ public class SQLElementList<E extends SQLElement<E>> extends ArrayList<E> {
 	
 	
 	
-	public <T, F extends SQLElement<F>> Map<T, F> getAllForeign(SQLFKField<E, T, F> foreignKey) throws ORMException {
+	public <T, P extends SQLElement<P>> SQLElementList<P> getReferencedEntries(SQLFKField<E, T, P> foreignKey, SQLOrderBy orderBy) throws ORMException {
 		Set<T> values = new HashSet<>();
 		forEach(v -> {
 			T val = v.get(foreignKey);
@@ -170,20 +170,61 @@ public class SQLElementList<E extends SQLElement<E>> extends ArrayList<E> {
 		});
 		
 		if (values.isEmpty()) {
-			return new HashMap<>();
+			return new SQLElementList<>();
 		}
 		
 		SQLWhereChain where = new SQLWhereChain(SQLBoolOp.OR);
 		values.forEach(v -> where.add(new SQLWhereComp(foreignKey.getPrimaryField(), SQLComparator.EQ, v)));
 		
 		
-		SQLElementList<F> foreignElemts = ORM.getAll(foreignKey.getForeignElementClass(), where, null, null, null);
+		return ORM.getAll(foreignKey.getForeignElementClass(), where, orderBy, null, null);
 		
-		Map<T, F> ret = new HashMap<>();
+	}
+
+	
+	public <T, P extends SQLElement<P>> Map<T, P> getReferencedEntriesInGroups(SQLFKField<E, T, P> foreignKey) throws ORMException {
+		SQLElementList<P> foreignElemts = getReferencedEntries(foreignKey, null);
+		
+		Map<T, P> ret = new HashMap<>();
 		foreignElemts.forEach(foreignVal -> ret.put(foreignVal.get(foreignKey.getPrimaryField()), foreignVal));
 		return ret;
 	}
 	
+
+	
+	public <T, F extends SQLElement<F>> SQLElementList<F> getReferencingForeignEntries(SQLFKField<F, T, E> foreignKey, SQLOrderBy orderBy, Integer limit, Integer offset) throws ORMException {
+		Set<T> values = new HashSet<>();
+		forEach(v -> {
+			T val = v.get(foreignKey.getPrimaryField());
+			if (val != null)
+				values.add(val);
+		});
+		
+		if (values.isEmpty()) {
+			return new SQLElementList<>();
+		}
+
+		SQLWhereChain where = new SQLWhereChain(SQLBoolOp.OR);
+		values.forEach(v -> where.add(new SQLWhereComp(foreignKey, SQLComparator.EQ, v)));
+		
+		return ORM.getAll(foreignKey.getSQLElementType(), where, orderBy, limit, offset);
+		
+	}
+
+	
+	public <T, F extends SQLElement<F>> Map<T, SQLElementList<F>> getReferencingForeignEntriesInGroups(SQLFKField<F, T, E> foreignKey, SQLOrderBy orderBy, Integer limit, Integer offset) throws ORMException {
+		SQLElementList<F> foreignElements = getReferencingForeignEntries(foreignKey, orderBy, limit, offset);
+		
+		Map<T, SQLElementList<F>> map = new HashMap<>();
+		foreignElements.forEach(foreignVal -> {
+			SQLElementList<F> subList = map.getOrDefault(foreignVal.get(foreignKey), new SQLElementList<>());
+			subList.add(foreignVal);
+			map.put(foreignVal.get(foreignKey), subList);
+		});
+		
+		return map;
+	}
+	
 	
 	
 	

src/main/java/fr/pandacube/java/util/orm/SQLFKField.java

@@ -2,12 +2,20 @@ package fr.pandacube.java.util.orm;
 
 import fr.pandacube.java.util.Log;
 
-public class SQLFKField<E extends SQLElement<E>, T, F extends SQLElement<F>> extends SQLField<E, T> {
+/**
+ * 
+ * @author Marc
+ *
+ * @param <F> the table class of this current foreign key field
+ * @param <T> the Java type of this field
+ * @param <P> the table class of the targeted primary key
+ */
+public class SQLFKField<F extends SQLElement<F>, T, P extends SQLElement<P>> extends SQLField<F, T> {
 
-	private SQLField<F, T> sqlPrimaryKeyField;
+	private SQLField<P, T> sqlPrimaryKeyField;
-	private Class<F> sqlForeignKeyElemClass;
+	private Class<P> sqlForeignKeyElemClass;
 
-	protected SQLFKField(SQLType<T> t, boolean nul, T deflt, Class<F> fkEl, SQLField<F, T> fkF) {
+	protected SQLFKField(SQLType<T> t, boolean nul, T deflt, Class<P> fkEl, SQLField<P, T> fkF) {
 		super(t, nul, deflt);
 		construct(fkEl, fkF);
 	}
@@ -36,7 +44,7 @@ public class SQLFKField<E extends SQLElement<E>, T, F extends SQLElement<F>> ext
 		return new SQLFKField<>(fkF.type, nul, deflt, fkEl, fkF);
 	}
 
-	private void construct(Class<F> fkEl, SQLField<F, T> fkF) {
+	private void construct(Class<P> fkEl, SQLField<P, T> fkF) {
 		if (fkF == null) throw new IllegalArgumentException("foreignKeyField can't be null");
 		try {
 			ORM.initTable(fkEl);
@@ -51,11 +59,11 @@ public class SQLFKField<E extends SQLElement<E>, T, F extends SQLElement<F>> ext
 		sqlForeignKeyElemClass = fkEl;
 	}
 
-	public SQLField<F, T> getPrimaryField() {
+	public SQLField<P, T> getPrimaryField() {
 		return sqlPrimaryKeyField;
 	}
 
-	public Class<F> getForeignElementClass() {
+	public Class<P> getForeignElementClass() {
 		return sqlForeignKeyElemClass;
 	}